Effect of shell growth and doping conditions of core-shell homojunction si nanowire solar cells

Effects of shell growth and doping conditions on the structural, optical and photovoltaic properties of core-shell homojunction Si nanowire (SiNW) arrays have been investigated. Core-shell nanowires were fabricated using a combination of metal-catalyzed electroless etching (MCEE) and thermal chemical vapor deposition (CVD) techniques. SiNWs formed by MCEE technique readily bundles with each other, disturbing the formation of radial p - n junctions surrounding them. CVD has made it possible to form uniform p-type Si shell layers on n -type SiNWs formed by MCEE technique. Results of SEM and Raman measurements reveal that electrical active B concentration can be increased with increase of shell thickness by increasing doping gas fluxes and growth time while keeping good crystallinity. Reflectivity measurements show an increase of light reflection in the visible range with increasing shell thickness. The short circuit current (I_sc) and fill factor (FF) closely depend on the shell growth time and the dopant gas flux for the growth of shell layers. These results show doping conditions to be a key parameter for core-shell homojunction SiNW solar cells.